1. Field of the Invention
This invention relates to a radar apparatus detecting a preceding object and measuring relative data, such as distance, direction and speed, of the detected object, and more particularly to a radar apparatus performing a two-dimensional scanning operation using a rotary polygon mirror having a plurality of mirror surfaces inclined at different angles, and further relates a vehicle safe distance control system incorporating this radar apparatus.
2. Related Art
Unexamined Japanese Patent Application No. 62-8119, published in 1987, discloses such a rotary polygon mirror having a plurality of mirror surfaces inclined at different angles.
This kind of radar apparatus is preferably used to perform a two-dimensional scanning operation using a laser beam, which is for example applied to a vehicle safe distance control system which detects a preceding vehicle and maintains a safe distance based on the detected distance between the radar and the preceding vehicle.
In general, using a rotary polygon mirror in the two-dimensional scanning operation is advantageous in costs, life cycle and reliability of the radar apparatus.